VLC for iOS can play all your movies and shows in most formats directly without conversion. You can synchronize media to your device using WiFi Upload, iTunes, Dropbox, or direct downloads from the web.
More about VLC Media Player for iOS
VLC for Mobile is a port of the free VLC media player to iPad, iPhone and iPod touch. It can play all your movies, shows and music in most formats directly without conversion. It allows file synchronization with Dropbox, GDrive, OneDrive, Box, iCloud Drive, iTunes, direct downloads and through WiFi sharing as well as streaming from SMB, FTP, UPnP/DLNA media servers and the web. VLC offers support for advanced subtitles including full SSA compatibility, multi-track audio, and playback speed control. Learn more.